Physical multimorbidity and depression: A mediation analysis of influential factors among 34,129 adults aged ≥50 years from low- and middle-income countries

Background There is a scarcity of literature on the association between physical multimorbidity (i.e., >= 2 chronic physical conditions) and depression among older adults, especially from low- and middle-income countries (LMICs). In addition, the mediators in this association are largely unknown. Therefore, we aimed to examine this association among adults aged >= 50 years from six LMICs (China, Ghana, India, Mexico, Russia, and South Africa), and to identify potential mediators. Methods Cross-sectional, nationally representative data from the Study on Global Ageing and Adult Health were analyzed. Depression was defined as past-12 months DSM-IV depression or receiving depression treatment in the last 12 months. Information on 11 chronic physical conditions were obtained. Multivariable logistic regression and mediation analyses were conducted. Results Data on 34,129 individuals aged >= 50 years were analyzed [mean (SD) age 62.4 (16.0) years; maximum 114 years; 52.1% females]. Compared to no chronic conditions, 2, 3, 4, and >= 5 chronic conditions were associated with 2.55 (95% CI = 1.90-3.42), 3.12 (95% CI = 2.25-4.34), 5.68 (95% CI = 4.02-8.03), and 8.39 (95% CI = 5.87-12.00) times higher odds for depression. Pain/discomfort (% mediated 39.0%), sleep/energy (33.2%), mobility (27.5%), cognition (13.8%), perceived stress (7.3%), disability (6.7%), loneliness (5.5%), and food insecurity (1.5%) were found to be significant mediators in the association between physical multimorbidity and depression. Conclusions Older adults with physical multimorbidity are at increased odds of depression in LMICs. Future studies should assess whether addressing the identified potential mediators in people with physical multimorbidity can lead to reduction in depression in this population.